Method of making hollow articles



Dec. 18, 1951 E EQM LLS 2,579,390

I METHOD OF MAKING HOLLOW ARTICLES 2 SHEETS-SHEET 1 Filed June 50, 1950 23 I Hg. 2.

8 35/,/,/2/ 8 lnvenfor 2 E/mer E. M/'//s Dec. 18, 1951 E, E, WLLS 2,579,390

METHOD OF MAKING HOLLOW ARTICLES I Filed June so, 1950 2' SHEETS-SHEET 2 4 22 q 2 /nvenf0r /'g, 5, E/merE. M///s Afforney Patented Dec. 18, 1951 UNITED STATES PAT ENT OFFICE 2,579,390

0.1! G HQLLOW ARILQLEfi Elme: Mills, H h an a Il Annllcotlom lune. $0, 5 0... S rial. No! 1.1 340 1 Claims.

Thi inven ion rela es. in gen eel. to e meth I of tebtleetih hollow articl s, ouch. as c htelhets and. particularly bottles. euhetahtielly ehtometh sally from. a tu oi la tic ma er al.

P ts n acquain d w th he methocle pr s ehtly n use for mahu eetuxh a eontemexs trout them lastic material are well were oi the a; therma -pla tic materiel; whleh will reqotze' mu h less complicated and. costly meemnem to ehnty ou A. furth r o je t of; my invention t the mm vision of. an. improved method. to: teotieetion of ollow art cles.v as. atoresa dl whereby. the output of each. ind idual fabrication machine. may be greatly increased.

A iur her o ject. f. my invention is the. hmvision of. a met od f r fabricat ng h low an titl s, s. aforesaid! which. lim ates. al oi the intermediate handling and steps present y re-- 1 quirecl between the aetual contain r iar rloetih process and the process. of preparin the. plast c materiel in. a suitable form to: tebrlcetloht Euxther obj cts and. pu poses o 111N511; tion will becomeapparent to. persons. t miller with this type or. quipment and. mahuteetur n process upon. reading the tollowlng. speeltleetloh ahdrefenjih to the. ac mpanying drawth t- In the. drawings:

Figu 1 is. e tzaementeryl lan view o: o mer chine su table 9 conducting my ptooete and vshows. a. ire ment of a. pl stic. extruding the Fi ure 2. is. a front,v elevetioh View ot e pelt of; mole. halves and. the su oextme heme thelfefor."

F gu e 3 is. e ngitudinal. eehtzel. teotloh view of. 84.1 open. mold.

Figure e is. e longitu lheh eentreh see lohel view of e. closed mold- Figure 5. is, a iregmehtm. stde,,e1evetloh View I o! an open mold.

' 1h executing the o jects an nurpetet of; my invention I employ a method .for fobxleotlhg: hell low articles. trom. softened tubular, plaetio Illa teliel-v Each h llow el' l le is termed. within one of. e. number n: movable thee. The diet a oloeecl 119 11 the tubu ar ma erie encl he ee tion Qt tubule: material contained within each die is lholvislue ly ex hded to the desited. s ze and shone.

applica i n is e eootlhuetlon nrpert Qt my-copeocling, enol e tloh entitled. lll eh e. or Me ting. Hollow Artie es..- fieriel No.1 118,335 filed October 3., 1.9%. end Be nt 21.51. 993- M1 .ehove islehtllled eopehcl he eoplicetion de serlhee one pzefehte l embodiment. of; e! machine suitable for carrying out the procegs, harem (11 eloteell h eumeleht clesprhgtioh of. thie mechm 1e ihelu led. hete h. to clarity the ooeretioh 01 my omeesh.

Retemhg o l-Fi re. 1,. the. num ral I were to emo tlins machine having, e e reuler table 3 ro etebhz mounted by meme of. the center ost 3. on e necleetel of any sultehle. type! oe eet l tenet. lluet eted. s nce it may be o any conven ional eohstmetlonh diel y ellghe l about. the perip er of. the table 2. are a plurality Qt mol s. t g, 1.), eeh hevlhg e. home including e. pl te 5 (Eig- 2.) sum port d above the table. 2.. b meene oi the. eupnort post 36-, Within the frame is mounted o. die or mold. block. cons ting of e. fixed lower m d halt 6 and. a movable up er mold half. L. The. upper mold. half. I i attached. to the. ve tical. guide. here 8 m1: v xtleel. sliding reciprocat on, e W oi rocetioo of th upper mold half I is. efieeted hrough the pietoh. 9 y mean o th dou l acting cylinder II! mounted on the plate. 5.

mold. hal es 5 and. 1 (flee. 3 and. 4.0 ea

t hove eh mtemal mo d. cavi H and. 12,. respect:

tive x lfhe mold cavities H. and l2 te, at one ehdl. each pzovicled. with e ne khert oh 3. end an. extended h el: poztioo l'he mold eevi tles. H and. 12 together with the neo p rtion I3..%I1Q3UHQQX1ZILQQQ neok p rtion 1 term the molding chamber...

he. uppe meld he t is Bl'Q QQQ ith an ope ing 15 thezethrou h. which comm nicate between the outs de surtaeeof the die hlo k and the mold cavi y l2 above. the exten ed. nec

nortloh l thereot- A holl w needle t, such as hypo lermio needle,v is dispo ed within the opehme l5 and. extent into the extehded EQl iQ l M. e: the mold. cavi y so that it memes. the extension of the hollow article formed within the. extended hee s polzt o which extensio is letter 2 .ovedl. 1 I

Th lateral ends. I! eml .8. of both the upoet end. lowe mole 'hel ee beveled, eqiecent. the

meld cavities. to the Jewe and 20.. re

needle I6 is supplied with a pressurized fluid" through the tube 23. The arrangement of the fluid conduits and the various flow control means for these fluids for regulating the operation of the mold and the needle are not described since they form no part of this invention and are fully dis- 4 terial is aligned with the mold, the separable halves of the mold are brought together, thus, closing the mold. As the mold is closed, the jaws l9 and 20 collapse the member of tubular material at each end of the mold. This pressing together .or collapsing of the member of tubular material occurs only between the jaws. The section of the member of tubular material within the mold is not aifeeted. JIhe jaws-i9; and 20 press the sides of the member of, tubular .material together sufficiently to seal each end of the section of tubu- :lar material within the mold against the passage of a fluid under pressure. Thus, each individual portion "or section of the member of tubular maclosed in my above-identified copending application. The same is true of the fluid conduits and controls for supplying the fluid chambers. 22.

The table 2 is'. positioned such that the central axis of each oith'e molds between the jaws l9 and becomes tangent, as the table rotates, to the longitudinal axis 2401' a source of hollow or tubular plastic materialsuch as the extrusion machine 25. The'upper mold half (is spaced apart from. the lower mold half 6 asthejmolds align with tubular material 26 issuing from the extrusion machine 25. The" upper mold half 1 is subsequently closed against the lower, mold hall} 6 and the tubular materiallwithinthe mold block expandedtosize. I f e g It will be understood that I have described only one of numerous possible structural embodiments of a machine capable of carrying out my process for making hollow 8.l tiC1 BS. QThlS description is presented for the sake of. clarity and is not to be considered as a limitation on my process. g In my process tubular, plastic material is supplied to the molds in a suitable condition for forming. The, term tubular is herein used to describe a hollow member,- although this hollow member needf not necessarily be cylindrical. The material may be existingjtubular forms which are passed through a machine which will heat them to a suitable temperature for blowing. Preferably, however, this operation is eliminated by extruding the tube as it is needed and feeding it directly from the extruder to the molding machine. In either case my invention contemplates a tube of material in condition for blowing being supplied to the'molding machine as a continuously moving column or member.

The molds are, ,one by one, successively moved into tangential alignment with this moving member of tubular material. The speed at which the molds are moved issynchronizedtothe rate of lineal movementoi', the member of tubular material. The angular velocity of the table. 2 and the lineal velocity or the tubular material may be synchronizedsuch that themolds are moved at the same speed as the tubular material or slightly faster than the tubular material to effeet a slight stretching of the tubular material. How the molds are aligned with the member of tubular material is not critical to my invention. Preferably, the molds are travelling along an endless path but the shape and the vertical or horizontal disposition of the plane of this path is immaterial. i

As the member of tubular material and the molds become aligned, the separable members 01 the mold, that is, the upper and lower mold halves, receive the member of tubular material between them. When the member 01 tubule! 31% terial clamped within each mold becomes a sealed,

fluid-tight chamber isolated from every other section and'from-tharest of the member of tubular material extending between the last mold to be closed and the source of the member of tubular material, I I s The action' of the Jaws I9 and 20 upon the member of tubular Imatrial is preferably a squeezing action rather than a cutting action. The recessing of the 'jaws permits a small neck of material to remain for connecting the sections within'each of the molds one to another and tothe tubular material issuing from the extruder. v

When the section of the member of tubular material within each mold has been isolated as a separate'.'sealed container by the jaws f9 and 20, this section is expanded to fill the mold cavity by admissidnof'agas or liquid through the needle l6. Theneedle pierces or punctures the section of the tubular material either as matter the mold'halves are clamped together. The flow of the gas or liquid through the needle is regulated to occur.only afterthe jaws have efl'ected the isolationof the section of tubular material within the individual mold. The temperature of the fluid admitted through the needle. may be regulated :to suit' the requirements of the particular material'or object being molded. The temperature of feachof the'molds may be regulated by means of the passage of suitable fluid through the fluid chambers 22.

When the small neck of compressed tubular material is permitted to remain between each molded section, the hollow articles are removed as a'continuous string from the molds. After removal, the individual articles are separated. Although removal of the articles as a string is preferable, they may be individually removed. Whenv suchis desired, the jaws l9 and 20 are designed either to sever the tubular material or to so nearly sever it that the individual articles become separated in the process of removal from the die. The portion of each of the articles formed-in the extended neck portion I 4 of the mold cavityis not designed to become a part of the finished .article. This portion is removed from the article when the article is processed after removal from the mold. Thus, the opening created by the piercing action of the needle does not appear in the finished product.

It is contemplated that eachof the steps of introducing the member of tubular material to the mold, closing the mold, sealing the tubular material at each end of the mold, expanding the tube within the mold and removing the molded articles irom the mold will each be performed wnnepom the molds and the tubular material. are continuously in motion. Since the movement of the .molds is continuous, the only limitation upon the production rate of a machine emthe article has been blown ploy'lng my process is the capacity of "the machine supplying the basic tubular material; f

The setting'of the material in the molds after may be regulated "by the temperature of the fluid circulated through the fluid chambers 22. The fluid used to expand the tubular material against the walls of the mold cavity may be either an inert gas, such as air, or an inert "liquid, or it may be a fluid having some treating eifect on the plastic, such as a hardening agent, or a coating-or coloring material. The composition of the plastic tubular material has been herein referred to as thermoplastic primarily because presently known types of thermo-setting. plastics are notsuitable to the type of operation above described; However, it will be clearly understood that this invention is not limited to the use of thermo-plasticmaterials as such, and used in the present specification and claims shall refer to any material having generally the necessary plasticity characteristics. g

It is possible to design each or the molds to have two individual mold cavities with a separate needle for introducing fluid to the tubular material in each cavity. Numerous other modifications of my process may be made, each without departing from the scope of my invention. It is not my intention, implied or otherwise, to exclude such modifications from the hereinafter appended claims unless specifically stated to the contrary in these claims.

I claim:

1. 'In a method for making plastic hollow ware,.

the steps which include: introducing softened, tubular, organic, plastic material into a mold; sealing said tubular material at each end of the mold against the passage of a fluid; piercing the tubular material within the mold for creating an opening; introducing a fluid into the tubular material within the mold through said opening under a positive pressure sufiicient to expand said plastic material to the shape of said mold.

2. In a method for making plastic hollow ware, the steps which include: providing a continuously moving tube of softened, organic, plastic material; successively hermetically isolating portions of said tube in individual mold chambers; moving said mold chambers at a speed synchronized with the movement of said tube; individually introducing a gas into each of said isolated portions under a positive pressure suflicient to expand said plastic material to the shape of said mold chamher.

3. In a method for making plastic articles, the steps which include: successively introducing softened, tubular, organic, plastic material into a plurality of individual molds; sealing said tubular material at each end of each of the molds against the passage of a fluid; piercing the tubular material within each of the molds for creat-- ing an opening; introducing a fluid under a positive pressure into the tubular material within each of the molds through said opening and thereby expanding said tubular material within each of said molds to the shape of said molds; removing the molded articles from said molds as a substantially continuous string.

4. In a method for making plastic articles, the steps which include: providing a continuously moving tube of softened, organic, plastic material; successively arranging a plurality of molds coaxially with said tube; moving said molds continuously, synchronizing the speed of said molds that the term 'thermo-plastic" as with the speed 01 said tupuiar matenal'; enema-- ually clamping eachof "saidmol'ds' 'about's'aid ta bular material; collapsing said-"tubular'material at each end of each of {said molds for isolating '5 the portion of said tubular material in "eachof said molds into a fluid-tight chamber; individually introducing into each of said isolated portlons a gas under a positive pressure sufiicient to expand said plastic material to theshape oi? said molds. 1

'5. In a method for making plastic hollow ware, the steps which include; providing a continuouslymoving tube of softened, organic, plastic material; providing a plurality of individualfmolds'; is moving said molds at a speed-synchronized to the movementof said "tube or material; surrounding said tube of material with" said molds; locally collapsing and sealing said tube of material against the passage of a'fiuid at' each end of each of said molds; introducing a fluid under a positive pressure into the portion of said tube of material within each ofsaid molds, said pressure being suiiicient to expand said plasticj material to the shape of said mold. Q' r 6. In a. method for 'makin'gplastic hollow ware having an open neck portion, the steps which include: successively introducing a tube of so!- tened, organic, plastic material into each of a succession of individual molds each having a main body cavity, a neck forming cavity and a neck extension forming cavity; forcing the sides of said tube together at each end of each of said molds for sealing said tube, and thereby forming a fluid-tight chamber within said tube and between said sealed ends; piercing said tube in said neck extension forming cavity; introducing a fluid into said chamber through said pierced opening under a positive pressure sufficient to expand said tube between said sealed ends, and thereby expanding said tube to fill said cavities of said mold; successively removing said expanded tube from said molds; removing said neck ex tension portion of said expanded tube.

7. In a method for making in a mold having a molding chamber including a main body cavity, a neck forming cavity and a neck extension cavity, a hollow, plastic container having an open neck portion, the steps which include: introducing softened, organic, plastic, tubular material into said mold; sealing against the passage of a fluid said tubular material at the extremities of said molding chamber; puncturing said tubular material in the neck extension portion of said mold cavity; introducing a fluid into said tubular material through the opening punctured therein under a positive pressure sufficient to expand said tubular material to the shape of said molding chamber.

8. In a method for making plastic articles, the steps which include: successively introducing softened, tubular, organic, plastic material into a plurality of individual molds; successively sealing said tubular material at each end of each of the molds against the passage of a fluid; successively piercing the tubular material within each of the molds for creating an opening; successively introducing a fluid under a positive pressure into the tubular material within each of the molds through said opening, and thereby expanding said tubular material within each of said molds to the shape of said molds; successively removing the molded articles from said molds as a substantially continuous string.

9. In a method for making plastic hollow ware having an open neck portion, the steps which include: successively introducing a, tube of softened, organic, plastic .material into each of a succession of molds each having a main body cavity, a neck forming cavity and a neck extension forming cavity; forcing the sides of said tube together at each end of each of said molds for sealing said tube and forming a fluid-tight chamber within said tube and between said sealed ends; piercing said tube in said neck extension forming cavity; introducing a fluid into said tube through said pierced opening under a positive pressure suflicient to expand said tube between said sealed ends, and thereby expanding said tube'to fill said cavities of said mold; removing said expanding tube from said mold.

10. In a method for making plastic hollow ware, the steps which include: providing a substantially continuous tube of said softened, plastic materials; presenting a succession of molds to said tube; locally collapsing said tube at each end of each of said molds and thereby successively creating a plurality of hermetically isolated portions, one in each of said molds; individually introducing into each of said-isolated portions a fluid under a positive pressure sufficient to expand said tube to the shape of said mold. r

Number 11. In a method for making plastic-hollow ware, the steps which include: providing a substantially continuous tube of softened, plastic material; presenting a succession of molds to said tube; locally collapsing and sealing said tube against the passage of a fluid at each end of each of said molds and thereby creating a plurality of hermetically isolated portions, one in each of said molds; individually introducing a, fluid intothe isolated portion in each of said molds under a positive pressure sufiicient'to expand said isolated portion to the shape of said mold.

ELMER E. MILLS.

REFERENCES CITED 0 The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 1,263,141 Strauss Apr. 16, 1918 1,654,647 Heist Jan. 3, 1928 2,187,432 Powers Jan. 16, 1940 2,192,507 Schavoir Mar. 5, 1940 2,321,319 Rempel June 8, 1943 2,515,093

Mills July 11, 1950 

